Mixed mellitate compounds

ABSTRACT

Mixed mellitate compounds useful as plasticizers for vinyl polymers, such as polyvinyl chloride homopolymers and copolymers, which have increased resistance to hydrocarbons have been prepared. The mixed mellitates of this invention are derived from trimellitic acid and trimellitic anhydride and contain two ester moieties derived from monofunctional alcohols and a third complex ester group obtained either by the reaction of a diol, a dibasic acid and a monofunctional alcohol or by the reaction of a diol and a monobasic acid.

United States Patent Hendrickriem et a1.

[ June 10, 1975 MIXED MELLITATE COMPOUNDS Inventors: Roland Hendrickriem, Oakville,

Ontario; Alfred Johannes Dieterman, Mississauga, Ontario, both of Canada Emery Industries, Inc., Cincinnati, Ohio Filed: Nov. 20, 1973 Appl. No.: 417,585

Assignee:

Foreign Application Priority Data Nov. 23, 1972 Canada 157257 U.S. C1. ..260/475 P; 260/3l.8 DR; 260/31.8 HR; 260/31.8 PQ; 260/31.8 AN; 260/3l.8 B; 260/31.8 G; 260/3l.8 W; 260/3l.8 DA; 260/404.8

Int. Cl. C07c 69/76 Field of Search 260/475 R, 475 P, 404.8

References Cited UNITED STATES PATENTS 12/1930 Young 260/475 P Primary Examiner-Lorraine A. Weinberger Assistant ExaminerE. Jane Skelly Attorney, Agent, or Firm-G. A. Baracka; .I. D. Rice [5 7] ABSTRACT cohol or by the reaction of a diol and a monobasic acid. 1

6 Claims, No Drawings MIXED MELLITATE COMPOUNDS BACKGROUND OF THE INVENTION Plasticizers derived from trimellitic acid and trimellitic anhydride are known and used extensively with vinyl halide resins. Tri(2-ethylhexyl) trimellitate, for example, has been demonstrated to be an effective plasticizer for polyvinyl chloride. Other simple trimellitate esters have been described by Paul C. Dougherty et al in their article entitled Vinyl Plasticizers from Trimellitic Anhydride, found in the Technical Papers, Volume VIII, presented at the Eighteenth Annual Technical Conference of the SPE in January, 1962. U.S. Pat Nos. 3,444,237 and 3,043,792 also describe the use of esters of cyclohexane-l,2,4-tricarboxylic acid and esters of trimesic acid as plasticizers for polyvinyl chloride polymers.

Trimellitate plasticizers, in general, have satisfactory volatility, viscosity and low temperature performance characteristics, however, their resistance to hydrocarbons is poor. For this reason they are generally not acceptable in applications where the plasticized resin compositions are exposed to hydrocarbons such as oil, gasoline and other solvents. This one shortcoming, that is, poor resistance to extraction by hydrocarbons, precludes their use in resin formulations for automotive applications such as ignition wiring insulation and the like.

It would be desirable if trimellitate plasticizers were available which had improved resistivity to hydrocarbons and which could be readily compounded with vinyl halide resins for use in automotive applications. It would be even more advantageous if the other properties typically associated with the use of trimellitate plasticizers were not adversely affected. These trimellitate plasticizers would be even more useful if they could be easily prepared and were relatively low cost materials.

SUMMARY OF THE INVENTION We have now discovered mixed trimellitate compositions useful as plasticizers for vinyl halide resins which have improved resistance to hydrocarbons. The mixed mellitates of this invention are derived from trimellitic anhydride and/or trimellitic acid and contain two simple ester moieties derived from saturated monofunctional alcohols containing from 1 to 22 carbon atoms and a third complex ester moiety obtained either by the reaction of a saturated diol containing 2 to 8 carbon atoms, a saturated dibasic acid containing from 4 to 22 carbon atoms and a saturated monofunctional alcohol containing from 1 to 22 carbon atoms or by the reaction of a saturated diol containing 2 to 8 carbon atoms and a saturated monobasic acid containing from 2 to 22 carbon atoms. The mixed mellitate plasticizers have improved resistance to hydrocarbon extraction without sacrificing any of the other desirable propertiescommon to trimellitates such as low volatility, low viscosity and low temperature performance. The mixed mellitates are useful with a variety of vinyl polymers but are especially useful with vinyl halide polymers, particularly polyvinyl chloride homopolymers and copolymers. The amount of plasticizer employed may range from about to about 100 parts by weight per 100 parts of the vinyl polymer. I

DETAILED DESCRIPTION The present invention relates to compositions of matter having the formula:

The present trimellitate compositions are preferably mixed esters derived from trimellitic acid or trimellitic anhydride and have two adjacent ester groups substituted on the aromatic nucleus. Mixed esters obtained from trimesic acid or hemimellitic acid or anhydride may also be useful. The preferred plasticizer compounds correspond to the formula wherein R represents the radicals defined above. From the formulait is observed that the preferred mixed m'ellitates are not a single molecular species but, in fact, consist of a mixture of three different isomers. This is a result of the method of preparation and in no way affects the effectiveness of the resulting plasticizer compositions. All of the possible isomers are useful plasticizers in accordance with the terms of this invention and may be individually employed or present as a mixture with one or both of the other isomeric forms. The trimellitate compositions may also contain up to about 10% by weight of byproducts arising from transesterification occurring during the synthesis.

The saturated bivalent radical A is derived from diols containing 2 to 8 ,carbon atoms. Especially useful diols for the present invention are ethylene glycol, 1,2- or 1,3-propanediol, 1,3-, 1,4- and 2,3-butanediol, pentanediols and hexanediols.

The saturated bivalent radical B, which is preferably an alkyl radical, is derived from dibasic acids containing from about 4 to about 22 carbon atoms. Typical acids useful in the formation of the complex ester group include succinic acid, glutaric acid, adipic acid,

3 4 pimelic acid, suberic acid, azelaic acid, sebacic acid, To obtain .the mixed mellitate compounds of this inundecanedioic acid, dodecanedioic acid, tridecanedivention any number of techniques may be employed, oic acid, decadecanedioic acid, pentadecanedioic acid, however, the usual procedure is to first react 1 mole of brassylic acid, and the like. Mixtures of acids of the trimellitic anhydride or trimellitic acid with 2 mols of above types may be employed. Especially useful dibasic 5 a monofunctional alcohol or alcohol mixture to form acids for the present invention include adipic acid and the trimellitate diester which is a mixture of three isosebacic acid. meric forms. This reaction is represented by the equa- The monofunctional alcohols from which the radicals tion:

0 i? i ii can OR R o 2 ROH-7 HOC ROC EOR Ho e E011 ROfi 30H i E ii 0 0 0 0 R R and R are derived when m 1, may range from Small amounts of monoester and triester materials may the simplest saturated alcohols up to alcohols containalso be present. Subsequent reactions with the diester ing 22 carbon atoms. These alcohols may be branched a e ondu ed n a step-wise manner by Charging the or straighbchain. R R and R may all be the same or reactants individually. With this procedure the trimellidifferent depending on the alcohols employed. Monotate diester is reacted with 1 mol of a suitable diol and functional alcohols useful for the present invention inwhen the reaction is complete, or essentially so, a mol clude methyl alcohol, ethyl alcohol, n-propyl alcohol, of dibasic acid in the case m l or a mol of monobasic isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, acid in the case m 0 is charged and the reaction consec-butyl alcohol, t-butyl alcohol, 2-ethylhexyl alcohol, tinued. Finally, in the m 1 case a monofunctional aln-octyl alcohol, lauryl alcohol, myristyl alcohol, cetyl cohol is charged to the reactor. Suitable catalysts may alcohol, stearyl alcohol, and the like. 25 be employed to facilitate any of the esterification reac- In the case that m O, the monofunctional alcohols tions involved. One such catalyst is dibutyl tin oxide. from which the radicals R and R are derived are as in- The intermediate products formed during any of dicated in the immediately preceding paragraph. R in these reactions, such as the diester or any of the subsethis case is preferably derived from. branched or quent products derived therefrom, may be isolated at straightchain saturated monocarboxylic acids containany stage in the process or the process may be coning from 5 to 22 carbon atoms. Mixtures of these acids ducted continuously by simply adding the next reactant may also be employed. Monofunctional acids useful for with or without additional catalyst when the prior reacthe present invention include valeric acid, caproic acid, tion is complete or essentially complete.

n-heptylic acid, pelargonic acid, caprylic acid, lauric Compounds of this invention find utility as plasticizacid, myristic acid, palmitic acid, stearic acid and araers for vinyl polymers such as polyvinyl chloride homochidic acid. polymers and copolymers. In addition to having the In a preferred form of this invention R R and R of usual characteristics associated with previously known the formula are saturated hydrocarbon radicals contrimellitate plasticizers such as good volatility, good taining from 4 to 18 carbon atoms and, more preferalow temperature properties and low viscosity, the

bly, alkyl radicals containing 6 to 12 carbon atoms. Exmixed mellitates also have markedly improved resiscellent plasticizer compositions result when A is an tance to extraction by hydrocarbons such as hexane alkyl radical containing from 2 to 4 carbon atoms, B is and oils. This is extremely important for automotive an alkyl radical containing from about 6 to 18 carbon wire applications where a high degree of resistivity to atoms and m is 1. Especially effective mixed trimellihydrocarbons is required.

tate plasticizer compositions have R R R R -H In accordance with the present invention the mixed such as the 2-ethylhexyl group, with A being derived mellitate compositions are useful for plasticizing vinyl from ethylene glycol or 1,2-propanediol or 1,3- polymers. The term vinyl polymers is intended to enbutanediol and B derived from adipic acid. The comcompass both homopolymers and copolymers derived plex ester group from vinyl monomers, that is, compounds containing the CH C group. Most commonly the vinyl polymers useful for this invention are prepared by the polymerization of one or more monomers selected from the group consisting of vinyl chloride; vinyl bromide; vinyl acetate; vinylidene chloride; lower allyl esters; vinyl alkyl ethers; and acrylic and methacrylic esters such as f these compositions, h m 1 ld h h ethyl acrylate, methyl acrylate, and methyl methacrylspective Structures ate; acrylic acid and methacrylic acid; acrylonitrile and methacrylonitrile; and the like. Typical copolymer compositions may be obtained by the copolymerization of vinyl chloride with vinyl acetate; vinyl chloride with ..cu '-'ic-icu n-coc u vinyl butyrate; vinyl chloride with vinyl propionate; vinyl chloride with vinylidene chloride; vinyl chloride E O with methyl acrylate; vinyl chloride with 2-ethylhexyl -ci-| -cu-'J;- cu 9- -c0c n acrylate; and vinyl chloride with two 'or more mono- CH O O mers such as mixtures of vinylidene chloride, and 2- 3 1i H ethylhexyl acrylate; and the like. The plasticizers are E 2 'Q Z T B 17 also useful for acrylonitrilebutadiene-styrene terpolymers, chloroprene polymers, butadiene-styrene copolymers, butadiene-acrylonitrile copolymers, polystyrene, polyacetals, and the like. Especially useful and effective plasticization is obtained when the present mixed mellitates are employed with polyvinyl chloride homopolymer and copolymers of vinyl chloride with one or more other copolymerizable vinyl monomers.

In general, the amount of mixed mellitate plasticizer used may range from about 5 to 100 parts by weight per 100 parts by weight of the vinyl polymer. Excellent results are obtained when about to about 70 parts by weight of the mixed mellitate is employed per 100 parts by weight of the polyvinyl chloride homopolymer or copolymer. Such compositions exhibit a high degree of resistivity to extraction withhydrocarbons such as oil and hexane and are especially useful for automotive wire coating applications.

The mixed mellitate compositions are incorporated into the vinyl polymers prior to curing, molding or extruding. They may be incorporated by mixing the powdered resin with the liquid plasticizer followed by mixing and/or kneading or they may be mixed on a heated mill. The plasticizer may be added-as such, in a masterbatch solution, or the plasticizer may be emulsified and the emulsion added to the polymeric material. In general the plasticized compositions have excellent milling characteristics and require no special processing. The mixed mellitates may be used in conjunction with other primary plasticizers such as dioctyl phthalate, diisooctyl phthalate, dioctyl adipate, trioctyl phosphate, various polymeric plasticizers, epoxides, and the like. They may also be incorporated with other compounding ingredients including antioxidants such as phosphites, amines and phenols; pigments and other colorants; fillers; lubricants; antisticking agents; curing agents; and the like. The mixed mellitate plasticizers and the various compounding ingredients may be prepared as a masterbatch and added to the polymer as such or the various ingredients may be mixed in separately.

The following examples illustrate the invention more fully, however, they are not intended as a limitation on the scope thereof. In the example all parts and percentages are on a weight basis unless otherwise indicated.

EXAMPLE I Into a glass reactor fitted with a stirrer, thermometer, fractionating column, condenser and nitrogen inlet were charged 192 grams (1 mol) trimellitic anhydride, 260 grams (2 mols 2-ethylhexanol and 0.5 grams dibutyl tin oxide catalyst. By maintaining the reaction mixture at 190C and 160 mm absolute pressure a steady reflux was obtained and the temperature at the top of thelcolumn maintained between 100 and 105C. After Step 1.

Step 2.

Step 3.

I Step about an hour the theoretical amount of water had been removed and the acid number of the product was 6 about 124 indicating the formation of the di-2- ethylhexyl trimellitate. At this point the vacuum was released by introduction of nitrogen into the system until atmospheric pressure was established in the reactor. Grams 1 mol) 1,3-butanediol was then charged with 0.5 grams dibutyl tin oxide while increasing the temperature to about 235C. After about one hour the acid value was 1.1 andthe product had a molecular weight of 520 (theoretical 506) with a hydroxyl value of 107 (theoretical- 1 11). Reaction was continued without isolation of the intermediates by introducing 146 grams (1 mol) adipic acid and an additional 0.5 grams dibutyl tin oxide into the reactor while maintaining the temperature at 235C-and applying a vacuum of 50 mm absolute pressure. After a reaction period of about 30 minutes indications were that this phase of the reaction was esjs entially'complete and 130 grams (1 mol) 2-ethyl hexanol was then added with additional dibutyl tin oxide catalyst. This final reaction step was carried out at 230C and mm absolute pressure for 1% hours. The final product had an acid-value of 4 and an average molecular weight of 750 (theoretical 746). Properties of the mixed mellitate composition are listed in Table I.

EXAMPLE II EXAMPLE III The reaction was repeated substituting 193 grams (1 mol) azelaic acid for the adipic acid. The acid value of the di-2-ethylhexyl trimellitate formed in the first step of the reaction was 127. The hydroxyl value of the productobtained after reaction with the l,3-butanediol was 113 (theoretical 111). The acid value of the final mixed mellitate product was 3. Other properties of the mixed mellitate composition are set forth in Table I.

EXAMPLE IV The same reaction procedure was employed to react 192 grams trimellitic anhydride, 390 grams 2-ethyl hex anol, 62 grams ethylene glycol and 193 grams azelaic acid. Samples taken after each of the 4 reaction steps had the following acid values:

After reaction with the 2-ethyl hexanol to form the diester AV= (theoretical 129) After reaction with the ethylene glycol AV=2.4 (theoretical 0) After reaction with the azelaic acid AV=91 (theoretical 86) After reaction with the 2-ethyl hexanol to cap'the complex ester group and givelhefinal product AV=1 (theoretical 0 Physical characteristics of the mixed mellitate composition are reported in Table I.

TABLE 1 PROPERTIES OF MIXED MELLITATES To demonstrate the utility of the mixed mellitate compositions as plasticizers for vinyl halide resins the mixed mellitate compositions of Examples l-lV were formulated as follows:

100 Parts Vinyl chloride resin (Geon 102 EP-FS B. F. Goodrich Chemical Co.) 2 Parts Ferro 1820 (barium-cadmium stabilizer produced by Federal Chemical) 1 Part Ferro 903 (liquid organic inhibitor produced by Federal Chemical) 55 Parts Plasticizer The resulting resin compositions had the following physical properties:

PLASTICIZER OF Example Example Example Example Percent Elongation 310 320 300 295 100% Modulus (PS1) 1800 1775 1650 1750 Tensile (PS1) 3300 3300 2995 2950 I Hardness (Ins/l 91/85 84/78 92/87 91/87 sec.)

study were as follows:

Weight Weight Loss After Loss After Extraction Extraction Resin Plasticized With: Withgllineral With Hexane Product of Example 1 1.7 9.8 Product of Example ll 2.2 13.0

Product of Example 111 2.04 10.07 Product of Example 1V 1.89 10.93 TOTM t 7.72 27.58

The preceding data clearly demonstrates that the products of this invention are excellent primary plasticizers and that they have markedly improved resistivity to oil and hexane extraction compared to a known trimellitate plasticizer.

We claim:v 1. A mixed mellitate composition of the formula wherein R R and R are saturated hydrocarbon radicals containing from 1 to 22 carbon atoms, A is a saturated bivalent hydrocarbon radical containing from 2 to 8 carbon atoms and B is a saturated bivalent hydrocarbon radical containing 2 to 22 carbon atoms.

2. The mixed mellitate composition of claim 1 derived from trimellitic acid or trimellitic anhydride and having the formula wherein R represents the radicals 0 I ll R R and-A-OCBCOR 3. The mixed mellitate composition of claim 2 wherein R R and R contain from 4 to 18 carbon atoms, A is an alkylene radical containing 2 to 4 carbon atoms and B is an alkylene radical containing from 6 to 20 carbon atoms.

4. The mixed mellitate composition of claim 3 wherein R R and R are radicals containing from 6 to 12 carbon atoms, A is derived from a diol selected from the group consisting of ethylene glycol, 1,3- propanediol, 1,2-propanediol, 1,3-butanediol, 1,4- butanediol and 2,3-butanediol and B is a bivalent radical derived from adipic acid or sebacic acid.

5. The mixed mellitate composition of claim 4 wherein R R and R are C l-1 radicals, A is derived from 1,2-propanediol and B is derived from adipic acid.

6. The mixed mellitate composition of claim 4 wherein R R and R are C 11 radicals, A is derived from 1,3-butanediol and B is derived from adipic acid.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,888,909 'Dated June 10, 1975 R. H. Riem and A. J. Dieterman Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the first page of the Patent, in the second line of the entry identified as data element [19] "Hendrickriem" should read Riem in the first line of the entry identified as data element [75] "Hendrickriem" should read Hendrik Riem Column 4, line 50, "CH =C should read CH =C Signed and Scaled this Attest:

RUTH C. MASON C. MARSHALL DANN K ffl (mmnissinner oj'Parems and Trademarks 

1. A MIXED MELLITATE COMPOSITION OF THE FORMULA
 2. The mixed mellitate composition of claim 1 derived from trimellitic acid or trimellitic anhydride and having the formula
 3. The mixed mellitate composition of claim 2 wherein R1, R2 and R3 contain from 4 to 18 carbon atoms, A is an alkylene radical containing 2 to 4 carbon atoms and B is an alkylene radical containing from 6 to 20 carbon atoms.
 4. The mixed mellitate composition of claim 3 wherein R1, R2 and R3 are radicals containing from 6 to 12 carbon atoms, A is derived from a diol selected from the group consisting of ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol and 2,3-butanediol and B is a bivalent radical derived from adipic acid or sebacic acid.
 5. The mixed mellitate composition of claim 4 wherein R1, R2 and R3 are - C8H17 radicals, A is derived from 1,2-propanediol and B is derived from adipic acid.
 6. The mixed mellitate composition of claim 4 wherein R1, R2 and R3 are - C8H17 radicals, A is derived from 1,3-butanediol and B is derived from adipic acid. 